Sync Job connector snapshot JSON incorrect

## Bug Description
The "filtering" field of the "connector" snapshot object should be an array, but when creating a new sync job from Kibana, the field is created as an object.

### To Reproduce
Steps to reproduce the behavior:
1. Create index for any connector
2. Click on 'Sync'
3. Select 'Full' or 'Incremental'
4. Check the new document created in the '.elastic-connectors-sync-jobs' index

## Expected behavior
The connector snapshot object should have a property "filtering" of type array, but it is an object.

## Environment
8.11

Reproduce the issue through Kibana by creating a connector index, starting a Full or Incremental sync, and inspecting the new document in the .elastic-connectors-sync-jobs index. Trace the sync-job connector snapshot serialization and verify that the filtering property is stored as an array rather than an object.

Written by the indexing model from the issue text.